Page 340 - Industrial Power Engineering and Applications Handbook

Protection of electric motors 12/319
Relevant Standards

IEC Title IS BS
60034-1/1996 Rotating electrical machines 4722/1992 BS EN:60034-1/1995
Rating and performance for rotating machines
60034-1 1/1978 Rotating electrical machines. Built-in thermal protection, rules for - BS: 4999-1 11/1987
protection of rotating electrical machines
60072-111991 Dimensions and output series for rotating electrical machines. Frame 123 111991 BS: 5000- 10/1989
number 56 to 400 and Flange number 55 to 1080 BS: 4999-141/1987
60072-2/1990 Dimensions and output series for rotating electrical machines. Frame 1231/1991 BS: 5000-10/1989
number 355 to 1000 and Flange number 1180 to 2360 BS: 4999-103/1987
60072-3/ 1994 Dimensions and output series for rotating electrical machines. Small 996/1991 BS: 5000-1 111989
built-in motors. Flange number BF 10 to BF 50
60298/1990 A.C. metal-enclosed switchgear and controlgear for rated voltages above 3427/1991 BS EN: 60298/1996
1 kV and up to and including 52 kV
60470/1974 A.C. contactors for voltages above 1 kV and up to and including 12 kV 9046/1992 BS: 775-2/1984
60644/1979 Specification for high-voltage fuse-links for motor circuit applications - BS EN: 60644/1993
6075 111983 Industrial platinum resistance thermometer sensors - BS EN: 60751/1996
60892/1987 Effects of unbalanced voltages on the performance of 39 cage induction
motors
60947/1999 Specification for low-voltage switchgear and controlgear - BS EN: 60947
60947-1/1999 Low-voltage switchgear and controlgear. General rules and test 13947-111993 BS EN: 60947-
requirements 111998
60947-3/1998 Switches and SFUSIFSUS 13947-3/1993 BS EN:60947-3/1992
60947-4- 111996 Contactors and motor starters. Electromechanical contactors and motor 13947-4-1/1993 BS ENz60947-4-
starters 111992
60947-5-1/1997 Control circuit devices and switching elements - electromechanical 13947-5-1/1993 BS EN : 60947-5-1/1992
control circuit devices
Relevant US Standards ANSUNEMA and IEEE
ANSI C.37.42/1989 Standard on distribution cut out and fuse links
ANSI C.37.47/1992 Specifications for distribution fuse disconnecting switches, fuse supports and current limiting fuses
NEMAMG 111993 Motors and generators ratings, costruction, testing and performance
NEMA-AB111993 Moulded case circuit breakers and moulded case switches up to 1000 V a.c. Rating more than 5000 A
NEMA-AB3/1996 Moulded case circuit breakers and their application, up to 1000 V a.c. Rating 5000 A and more
NEMAIFU-111986 Low-voltage cartridge fuses

Notes
1 In the tables of relevant Standards in this book while the latest editions of the standards are provided, it is possible that revised editions
have become available. With the advances of technology and/or its application, the updating of standards is a continuous process by
different standards organizations. It is therefore advisable that for more authentic references, readers should consult the relevant
organizations for the latest version of a standard.
2 Some of the BS or IS standards mentioned against IEC may not be identical.
3 The year noted against each standard may also refer to the year of its last amendment and not necessarily the year of publication.

during the switching operation of the motors. Max. voltage variation from
- - the average voltage x 100% (12.1)
Average voltage
List of formulae used
Stator current on an unbalanced voltage
Voltage unbalance (negative phase sequence) I, = vr (12.2)
S l2
R, +R; +-xR; +[X, +SXSSX;]~
Voltage unbalance and